Straining and stop valve

ABSTRACT

A fluid filtering stop valve having a body with a cylindrical chamber having a circumferential sidewall with inlet, outlet and flush ports, and a cylindrical plug member rotatably disposed in the chamber. The plug member has spaced apart first and second circular plates with an off-center filtering screen extending therebetween. The plug member is rotatably between a filtering position in which the screen is located in the fluid flow between the inlet and outlet ports, a backflushing position in which the screen is located in the fluid flow between the inlet and flush ports, with the filtering side of the screen toward the flush port, and a closed position in which an arcuate plate washer loosely retained between the first and second plates is positioned to seal the flush and outlet ports. In the filtering position the washer seals only the flush port and in the flush position the washer seals only the outlet port. The screen uses outwardly diverging ribs to reduce lodging of material between the ribs. A second screen filters the fluid from the inlet port during backflushing.

This application is a division of U.S. Pat. No. 4,722,794 granted Feb.2, 1988.

DESCRIPTION

1. Technical Field

This invention relates generally to devices for removing foreignparticles from a fluid stream, and more particularly, to a straining andstop valve, especially for use in farm irrigation lines having smallstones and other debris in the incoming irrigation water.

2. Background Art

Many farmers require irrigation on a regular basis for the production ofsuitable crops. Irrigation is frequently accomplished by the use ofirrigation lines set in the fields with sprinkler heads spaced atcertain intervals. Often a sprinkler head will clog due to the presenceof a small stone or accumulation of other debris in the sprinkler lineor in the sprinkler head itself, requiring the supply of water to beturned off and the debris removed. The problem is greatest when thefarmer uses less than clean and clear water, such as that from anirrigation ditch. Water flowing through such a ditch continually carriesforeign particles to the sprinkler heads, which will clog and renderthem inoperative.

Common screening devices can be added in these irrigation lines;however, they are of limited value due to the nature and frequency ofcleaning them. First, to clean the in-line screen, the water through theirrigation line must be shut off. The screen must then be removed andthe foreign particles brushed or washed away. Finally, the screen mustbe fitted back in line and the water once again turned on. Many times,the water shut-off valve will be some distance from the clogged screen,and many sprinkler heads will be shut down while the cleaning operationoccurs. This makes the operation time-consuming and inefficient. If noscreening mechanism is used, the farmer will still need to go throughthe shut-off and cleaning procedure when a sprinkler head is clogged.

In the past, straining valves, such as those . shown in British Pat. No.16,460 and U.S. Pat. Nos. 8,052,237; 999,532; 3,348,694; 4,056,474 and4,351,727, have been designed for the straining of fluids. Thesedesigns, however, have drawbacks. The designs may be too complicated indesign, difficult or impossible to mold, or expensive to construct orassemble. The use of a diversion channel in the valve body, as describedin U.S. Pat. No. 805,237, makes separation of the body from a moldimpossible using current plastic injection molding techniques. Thehollow valve plug described in British Pat. No. 16,460 (see FIG. 5) issimilarly impossible to mold and could not be economically manufactured.In today's economy, if a valve cannot be inexpensively molded of plasticas a production part, the valve will not be competitive.

DISCLOSURE OF THE INVENTION

The present invention resides in a fluid filtering stop valve having adesign which may be inexpensively manufactured by well-known productionline molding techniques. The valve has a body having a cylindricalchamber with a circumferential sidewall. The sidewall has an inlet portand an outlet port, with a flush port position therebetween. The inletand outlet ports are positioned substantially diametrically oppositeeach other. The valve also includes a cylindrical plug member rotatablydisposed in the chamber.

The plug member has spaced-apart first and second substantially circularplates with a filtering screen extending therebetween. The screen has afiltering side for trapping particulate matter in the fluid flow throughthe valve. The plug member is rotatable between first, second, and thirdpositions. In the first position, the screen is located in the fluidflow between the inlet and outlet ports, with the filtering side towardthe inlet port for filtering. In the second position, the screen islocated in the fluid flow between the inlet and flush ports with thefiltering side toward the flush port for back-flushing. The screen ispositioned off the diametrical center line of the plates to position thescreen for sufficient fluid flow therethrough from the inlet port to theflush port to backflush the screen's filtering side when the plug memberis rotated into the second position. In the third position, the valve isclosed to stop all fluid flow.

The plug member further includes an arcuate seal positioned between theplates along a perimeter thereof. The seal is loosely retained betweenthe plates for movement into sealing engagement with the side wall ofthe silt chamber in response to fluid pressure in the chamber. The sealis sized to seal the flush port when the plug member is rotated into thefirst position, to seal the outlet port when the plug member is rotatedinto the second position, and to seal the flush and outlet ports whenthe plug member is rotated into the third position.

The chamber has an open end to receive the plug member and an opposed,closed end wall. The second plate of the plug member is positioned injuxtaposition with the end wall, and slidably engages the end wall. Theend wall has a circular aperture sized to rotatably receive andreleasably retain a retainer member fixedly attached to the second plateand projecting outwardly therefrom. The retainer member has asubstantially half round resilient shaft portion supporting a laterallyprojecting bulb portion. The bulb portion is positioned on the shaftportion a distance from the second plate sufficient to maintain the plugmember within the chamber during operation of the valve. In particular,the bulb portion is spaced at a distance from the second platesubstantially equal to the thickness of the end wall. The shaft portionhas a center of curvature substantially corresponding to the centerpoint of the end wall aperture.

The second plate has an indexing member fixedly attached thereto andprojecting outwardly therefrom, and . the end wall has an arcuate slotsized to receive and limit movement of the indexing member between endlimit positions corresponding to the first and second positions of theplug member. The indexing member coacts with the slot to limit rotationof the member between these positions.

The filtering screen includes a plurality of generally transverselyoriented ribs positioned in back to back relationship. The ribs on thefiltering side of the screen having one directional orientation areoutwardly tapered to provide an outwardly diverging space betweenadjacent ribs. The tapered ribs have a generally triangular crosssection. In a presently preferred embodiment of the invention, the ribson both sides of the screen have a tapered shape to provide a reversiblescreen. Using ribs with a triangular cross section, the ribs with onedirectional orientation are positioned to have their flat bases inback-to-back relationship with the flat bases of the ribs with oppositedirectional orientation.

The first and second plates have guides slidably and removably receivingthe screen, and retain the screen against lateral movement in responseto fluid flowing therethrough. The plates are held in fixed,spaced-apart relation by a plurality of support posts extending betweenthe plates. One of the support posts is positioned to engage and preventlongitudinal movement of the screen between the guides in a directiontoward the one support post. The first and second plates each have acircumferential edge groove with an O-ring disposed in each of thegrooves.

An inward face of the arcuate seal is positioned in proximity with anedge portion of the screen. The seal has ears projecting inwardly fromthe inward seal face which are spaced apart sufficiently to receive andgrasp the screen edge portion therebetween. A pair of the support postsare spaced apart and positioned to engage and limit inward radialmovement and circumferential movement of the seal, while allowingoutward radial movement of the seal for engaging the sidewall.

The valve further includes means for manually rotating the plug member,and a second filtering screen extending between the first and secondplates. The second screen is positioned to filter fluid flowing into thechamber from the inlet port when the plug member is rotated into thesecond position for backflushing. The second screen is orientedgenerally transverse to the first screen.

Other features and advantages of the invention will become apparent fromthe following detailed description, taken in conjunction with theaccompanying drawings.

Brief Description of the Drawings

FIG. 1 is an isometric view of a valve embodying the present invention.

FIG. 2 is an isometric view of the plug assembly of the valve shown inFIG. 1, showing the primary and second filter screens and the arcuateplate washer removed from the assembly.

FIG. 3 is a reduced, sectional view taken substantially along the lines3--3 of FIG. 1 showing the valve in the filtering mode.

FIG. 4 is a reduced, fragmentary, sectional view taken substantiallyalong the lines 4--4 of FIG. 1.

FIG. 5 is a sectional view of the chamber and plug assembly of the valveshown in FIG. 1, showing the plug assembly rotated for filtering.

FIG. 6 is a sectional view of the chamber and plug assembly of the valveshown in FIG. 1, showing the plug assembly rotated into the closed mode.

FIG. 7 is a sectional view of the chamber and plug assembly of the valveshown in FIG. 1, showing the plug assembly rotated into the backflushingmode.

FIG. 8 is an isometric view of the primary filter screen of the valve ofFIG. 1.

FIG. 9 is an enlarged, fragmentary, sectional view taken substantiallyalong the lines 8--8 of FIG. 8.

BEST MODE FOR CARRYING OUT THE INVENTION

As shown in the drawings for purposes of illustration, the presentinvention is embodied in a valve, indicated generally by referencenumber 10. The valve 10 includes a valve housing or body 12 having aflanged, exteriorly threaded inlet portion 14 and a flanged, interiorlythreaded outlet portion 16. The inlet and outlet portions 14 and 16permit threaded coupling of the valve 10 between conduits, such as aconduit 17a from a water source and a conduit 17b leading to a sprinklerhead or other water distribution device.

The body 12 of the valve 10 has a cylindrical chamber 18 axiallyoriented transverse to the inlet and outlet portions 14 and 16, andpositioned therebetween. A rotatable valve plug assembly 20 is removablydisposed within the chamber 18 for controlling the flow of fluid throughthe value 10. The flow of fluid is shown by arrows in the drawings.

An inlet port 22 of the chamber 18 communicates fluid between the inletportion 14 and the chamber, and an outlet port 24 of the chambercommunicates fluid between the chamber and the outlet portion 16. Thechamber 18 also has a flush port 26, which, as will be described in moredetail below, serves as an exhaust to the atmosphere for dischargingfrom the chamber any particulate matter caught by the valve.

The cylindrical chamber 18 has a cylindrical interior sidewall 28through which the inlet, outlet and flush ports 22, 24 and 26 pass. Theinlet and outlet ports 22 and 24 are positioned diametrically oppositeeach other, with the flush port 26 being positioned circumferentiallyhalfway therebetween. One axial end 30 of the chamber 18 is opened forreceiving the plug assembly 20 during assembly, and the opposite end isclosed by an end wall 32 having a centrally located opening 34therethrough and an interiorly facing arcuate slot 36 therein. The endwall opening 34 releaseably receives a resilient member 38 of the plugassembly 20, which rotatably retains the plug assembly within thechamber 18, and the slot 36 receives an indexing tab 40 of the plugassembly, which limits the rotation of the plug assembly withinpredetermined end limits.

The plug assembly 20 includes a circular top plate 42 and a circularbase plate 44, held in fixed, spaced-apart relation by first throughfourth support posts 46, 48, 50 and 52 extending between and fixedlyattached to the inward faces of the plates. As best shown in FIG. 4, theplates 42 and 44 are spaced apart such that with the plug assembly 20fully inserted into the chamber 18 for operation, the outward face ofthe base plate 44 slidably engages the inward face of the end wall 32,and the outward face of the top plate 42 is flush with the open end 30of the chamber.

The top and base plates 42 and 44 each have a circumferencial edge wallgroove 54 sized to receive and retain a conventional O-ring 56 toprovide a fluid-tight seal between the plates and the interior sidewall28 of the chamber 18. The inlet, outlet and flush ports 22, 24 and 26are located in the sidewall 28 between the top and bottom base plates 42and 44. A manually operable handle 57 projects from an outward face ofthe top plate 42 for rotation of the plug assembly 20 during operation.

The plug assembly 20 further includes a primary filter screen 58removably retained and supported between the top and base plates 42 and44 by guides 60. Each guide 60 comprises a pair of elongated ridgesprotruding inwardly from the inward face of one of the plates 42 and 44.The ridges of the guides 60 are spaced apart sufficiently to slidablyreceive and retain an edge portion of the screen 58 therebetween.

The screen 58 is also retained and supported by the first support post46. The first support post 46 has an L-shape with a short leg portion46a positioned at and transverse to one end of the guides 60, toward anedge portion of the plates 42 and 44. An edge portion of the screen 58is received and retained in an inwardly facing channel 62 of the shortleg portion 46a. As such, the short leg portion 46a preventslongitudinal movement of the screen 58 relative to the guides 60 in onedirection and also supports the screen against lateral movement underthe force of the fluid flow.

The screen 58 is positioned off the diametrical center line of the topand base plates 42 and 44, as are the guides 60 and the first supportmember 46, sufficiently to allow fluid flowing from the inlet port 22 toenter the chamber 18 primarily on the side of the screen opposite afiltering side 64 of the screen when the plug assembly 20 is rotated forbackflushing, as shown in FIG. 7. The screen 58 is positioned, however,transverse to the fluid flow between the inlet and outlet ports 22 and24 when the plug assembly 20 is rotated for filtering, as shown in FIGS.3 and 5. With this off-center positioning of the screen 58, no internalor external diversion channels are required and the chamber 18 can bemolded with a simple cylindrical shape.

As best shown in FIGS. 8 and 9, the screen 58 is formed by a pluralityof transversely oriented ribs 66. Each of the ribs 66 has asubstantially triangular cross-section with a flat base 68 and an apex70. In the presently preferred embodiment of the screen 58, the flatbase 68 of each rib 66 faces inward, placing the flat bases of the ribswith one directional orientation in back-to-back relationship to theflat bases of the ribs with the transverse directional orientation. Theapex 70 of each rib 66 faces outward. A frame 72 defines the edgeportions of the screen 58. A center support 73 adds structural rigidityand strength to the screen 58.

With such a shape, the screen 58 can be easily molded and is reversible,so that regardless of which side of the screen is serving as thefiltering side 64, the ribs 66 present an inwardly converging profile tofluid passing therethrough for filtering. Consequently, particulatematter trapped by the screen 58 on the filtering side 64 is less likelyto become tightly compacted and lodged between the ribs 66, or to adhereto the ribs. Since the ribs 66 of the screen 58 present an outwardlydiverging profile to the fluid passing therethrough for backflushing,the cleansing of the screen is more efficient and effective. As usedherein, particulate matter includes particles as well as debris andforeign matter of any shape and size.

The plug assembly 20 has an arcuate plate washer 74 retained between thetop and base plates 42 and 44, at the perimeter of the plates, andextending circumferentially about a portion thereof. The washer 74 hassubstantially the same radius of curvature as the top and base plates 42and 44, and is loosely held in place between the plates by the secondand third support posts 48 and 50. The support posts 48 and 50 arepositioned one to each side of the screen guides 60, toward an oppositeedge portion of the plates 42 and 44 from the first support post 46, andposition an inward face 76 of the washer 74 adjacent to an edge portionof the screen 58. The inward face 76 of the washer 74 is provided with apair of ears 78 spaced apart to receive and retain the edge portion ofthe screen 58 therein. The ears 78 lightly grasp the screen 58 and serveto hold the washer 74 in place during assembly of the plug assembly 20,particularly when the plug assembly is being inserted into the chamber18, and serve to support the screen against lateral movement duringoperation of the valve 10.

The second and third support posts 48 and 50 have shoulders formed toreceive the end portions of the washer 74 and prevent significantcircumferential or radially inward movement of the washer. The washer 74is, however, free to move radially outward responsive to fluid pressurein the chamber 18 to press the washer into tight sealing engagement withthe interior sidewall 28 of the chamber and thereby prevent the flow offluid through one or more of the inlet, outlet or flush ports 22, 24 and26, as will be described in more detail below. While the washer 74 hassufficient rigidity to be self-supporting and hold its shape, it issufficiently flexible to generally conform to the interior sidewall 28of the chamber 18 under fluid pressure and form a tight seal. The use ofthe separate sealing washer 74 avoids the difficulty of precisely sizinga plug so that its sidewalls provide a sufficient sealing of the portsin the valve chamber wall.

A second filter screen 80 may also be incorporated as part of the plugassembly 20 for filtering fluid entering the chamber 18 from the inletport 22 for backflushing the primary screen 58. The second screen 80 isremovably retained and supported between the top and base plates 42 and44, and is oriented substantially perpendicular to the primary screen58. An edge portion of the second screen 80 is slidably received andretained by a channel 82 formed in the short leg portion 46a of thefirst support post 46, and an opposite edge portion of the screen isslidably received and retained by a slot 84 extending fully through thefourth support post 52.

The resilient member 38 of the base plate 44 has a half-round shankportion 86 which resiliently supports a half-round bulb portion 88. Thebulb portion 88 projects laterally from the shank portion 86 and isspaced along the shank portion away from the outward face of the baseplate 44 by approximately the thickness of the end wall 32 of thechamber 18. The shank portion 86 is positioned on the base plate 44 soas to have a center of curvature corresponding to the center point ofthe end wall opening 34. As such, the bulb portion 88 is deflectedradially inward when inserted into the end wall opening 34; and afterpassing therethrough, the resiliency of the shank portion 86 moves thebulb portion radially outward to provide a snap fit and retain the plugassembly 20 within the chamber 18. The plug assembly 20 is easilyremoved from the chamber 18 by pressing the bulb portion 88 inwardly andpulling on the handle 57 of the plug assembly. With such a design, theresilient member 38 is easy to mold and facilitates assembly of thevalve 10.

In operation, the valve 10 has three basic modes. The normal operatingor screening mode is shown in FIGS. 3 and 5, in which the primary screen58 is positioned transverse to the flow of fluid from the inlet port 22to the outlet port 24. Particulate matter (not shown) is filtered fromthe fluid by the screen 58 and builds up on the upstream filtering side64 of the screen. The filtered fluid passes out of the chamber 18through the outlet port 24, and the flush port 26 is sealed by thearcuate plate washer 74. With the plug assembly 20 rotated to thefiltering position shown in FIGS. 3 and 5, the indexing tab 40 is at oneend limit of the arcuate slot 36, thereby preventing furthercounterclockwise rotation of the plug assembly.

To place the valve 10 in a closed mode to stop the flow of fluid fromthe outlet port 24, the plug assembly 20 is manually rotated clockwiseusing the handle 57 to the position shown in FIG. 6. In this mode, thewasher 74 is positioned over the flush port 26 and the outlet port 24 tostop all fluid flow from the valve 10.

The valve is shown rotated into the back flushing mode in FIG. 7. Inthis mode, the washer 74 is positioned over only the outlet port 24. Theoff-center primary screen 58 is positioned substantially to one side ofthe inlet port 22, in the path of fluid flow between the inlet port andthe flush port 26, with the filtering side 64 of the screen downstreamof the flow. In such manner, the fluid flow easily and completelydislodges any particulate matter trapped in the screen 58 from theoutwardly diverging ribs 66 and flushes the particulate matter out ofthe flush port 26 and clear of the valve 10.

In backflushing mode, the second filter 80 is positioned transverse toand over the inlet port 22 to trap any particulate matter in the fluidused to flush the primary screen 58. Since the fluid need flow for onlya short period of time to backflush the primary screen 58, the secondscreen 80 will infrequently need cleaning and can be convenientlycleaned during those times when fluid to the valve 10 is turned off.Cleaning of the second screen 80 is accomplished by removal of the plugassembly 20 from the chamber 18, and sliding the second screen from theplug assembly. With the plug assembly 20 rotated to the flushingposition shown in FIG. 7, the indexing tab 40 is at an end limit of thearcuate slot 36 opposite the end limit for the filtering position, andfurther clockwise rotation of the plug assembly 20 is prevented.

In the presently preferred embodiment of the invention, the top and baseplates 42 and 44, the first through fourth support posts 46, 48, 50 and52, the resilient member 38, the guides 60, and the handle 57 of theplug assembly 20 are molded as one integral part. Furthermore, all partsof the valve 10 may be inexpensively injection molded.

It will be appreciated that, although specific embodiments of theinvention have been described herein for purposes of illustration,various modifications may be made without the parting from the spiritand scope of the invention. Accordingly, the invention is not limitedexcept as by the appended claims.

I claim:
 1. A rotary fluid stop valve having a structure whichfacilitates its manufacture by well-known molding techniques,comprising:a body having a cylindrical chamber with a circumferentialinterior cylindrical sidewall, said sidewall having an inlet port and anoutlet port; a substantially cylindrical plug member rotatably disposedin said chamber, said member having spaced-apart first and secondsubstantially circular end plates connected to said plug member, saidplates each having a peripheral seal engaging the interior sidewall ofsaid chamber, said plug member having an arcuate sealing platepositioned between said end plates along a perimeter thereof, saidsealing plate being loosely retained between said plates for movementinto sealing engagement with said interior sidewall in response to fluidpressure in said chamber; said plug member being rotatable between atleast a first position wherein the ports are open to allow passage offluid therebetween and a second position wherein at least one of saidports is blocked by said arcuate sealing plate; said sealing plate beingcurved of the shape of the cylindrical sidewall, the curved sealingplate being smooth, uniform, non-point loaded, and larger than the portto be closed so that the sealing plate can slide over the port to beclosed in a direction parallel to the curve of the cylindrical sidewallwhile exposed to fluid pressure in the direction perpendicular to thecylindrical sidewall.
 2. The valve of claim 1, said body being capableof being removable from a mold in one direction, and said circular endplates being integrally connected to said plug member.
 3. A rotary valvehaving a body with a cylindrical chamber having:a cylindrical sidewallhaving at least two ports therein; an axial bore defined by thecylindrical sidewall a plug member fitted within said axial bore of saidchamber and having a pair of opposite circular flat end plates fittedwith peripheral seals for closing said axial bore; and separate sealingmeans fitted between said circular plates and movable radially outwardlytoward said chamber sidewall in overlapping relation to one of saidports in response to fluid pressure in said chamber to close one of saidports and prevent passage of fluid through said port, said plug memberbeing rotatable in said axial bore to move said sealing means out of anoverlapping position with said port to allow free passage of fluidthrough said port; said sealing means being curved of the shape of thecylindrical sidewall, the curved sealing means being smooth, uniform,non-point loaded, and larger than the port to be closed so that thesealing means can slide over the port to be closed in a directionparallel to the curve of the cylindrical sidewall while exposed to fluidpressure in the direction perpendicular to the cylindrical sidewall. 4.The valve of claim 3, said sealing means including a flexible arcuateplate loosely held in said plug member, said flat end plates each havingsupport posts for receiving the arcuate plate washer for preventingcircumferential and radially inward movement, but allowing freeoutwardly radial movement.
 5. The valve of claim 4, wherein said valveis plastic and said body being capable of being removed from a mold inone direction, and said circular end plates being integrally connectedto said plug member.
 6. The valve of claim 3, wherein said peripheralseals are o-ring seals each housed in a peripheral groove in itsrespective circular end plate.